In conventional wireless mesh networks, mesh devices have the ability to perform several types of operations:                forwarding frames received from a source device and intended for a destination device,        consuming frames, received from a source device, and used during sequence of operations of local applications of the device, and        They can generate frames during operating sequences of local applications.        
These operations do not mutually exclude each other, which means that applications running on a mesh device may generate frames concurrently to frames that the mesh devices receive and have to forward
In most existing implementations for WMNs, both types of frames, i.e. generated frames and received frames are handled equally when it comes to transmitting them to a receiving node. Indeed, frames of local origin and frames of remote origin are stored in the same transmission queue, and are sorted and transmitted according to their order of occurrence.
However, frames of both origins do not experience the same loss before reaching the transmission queue, depending on their origin. Frames generated by local applications do not traverse a transmission medium and, accordingly, do not experience any frame loss. For these frames, frame dropping occurs only if a lower layer buffer is full, which means that, in most cases, local applications easily store their frames in the local transmission queues.
On the contrary, frames coming from another mesh device have to traverse the wireless medium, which means that they are less likely to be successfully stored in the mesh device's transmission queue, because they may experience frame loss during crossing of the medium. Thus, the transmission queue may contain more generated frames than received ones.
Moreover, transmission rate on the wireless medium is limited, whereas applications locally running at mesh devices may generate frames at a higher rate. Consequently, both the limited incoming traffic rate and the reduced reception success probability of frames received from external devices increase the probability for these frames to be dropped at the transmitting mesh devices.
In addition, if p denotes the frame dropping probability on a single transmission link, the probability of a successful transmission over a chain of n equal and independent links is (1−p)n. Thus, the frame dropping probability increase with every additional hop, which means that frame transmissions of devices that are close to the intended destination experience better performance than frame transmissions that still have to traverse a large number of hops.
Accordingly, it appears that current implementations using equal treatments for both types of frames present major drawbacks in always giving precedence to frames of local origin, thus leading to bad performance of multi-hop transmissions, and also by offering different qualities of service and overall performance to users situated in different locations in the network.